How to Choose a Suitable Glucometer

A blood glucose meter or glucometer is a device used to measure the level of glucose in the blood. Diabetic patients use it to monitor their blood sugar levels, helping them regulate their insulin intake if necessary. Glucometers are typically used with test strips to collect blood drops. However, in recent years, less invasive and restrictive alternatives have emerged.

Given the global prevalence of diabetes, the evolution of blood glucose monitoring systems has become a major global health issue. 

How does a glucometer work?

Glucometers can be divided into three different types: invasive, non-invasive, and continuous. 

1. Invasive: Measurement is conducted by using a lancet, insulin, and test strips to draw a blood sample. These components are typically sold in a kit for first-time buyers and must be replaced at pharmacies for new test strips and insulin. While there are limitations for users, this type of glucometer is the most accurate method of measurement. 

2. Non-invasive (or minimally invasive): In recent years, various measurement systems in the form of physico-chemical sensors have appeared on the market, which contact the measurement area (usually the arm). By scanning the area with the glucometer, blood sugar levels can be obtained almost immediately. This is a real innovation for diabetic patients who no longer need to inject themselves multiple times daily or replace test strips and insulin.

However, market options are limited, and results so far have shown that these offered systems find it hard to be as accurate as invasive systems. Another drawback is that sensors cannot remain consistently in the original position. 

3. Continuous glucose monitoring (CGM): In this case, the glucometer provides continuous measurement. Patients usually wear this device on their arm and carry it around. This type of model generally has an implantable sensor with a remote transmission system. It measures glucose levels in the interstitial fluid and can more accurately assess changes in blood sugar levels over long periods. This continuous system reduces patient stress as they no longer need to prick their fingertips daily. 

However, continuous systems have their own limitations, such as maintenance and learning to use the equipment. Difficulties in understanding and interpreting data, sensor malfunctions, and differences between capillary blood glucose measurement and values displayed by continuous glucose monitoring could be frustrating and might lead to users deciding not to use such devices. 

What are the most important features of a glucometer?

Glucometers must be tailored to meet each patient's needs. Therefore, before purchasing a glucometer, it is necessary to consider several factors, such as the convenience of use and transportation, the unit of blood glucose measurement displayed, and the chip (code) used. 

1. Ease of use: The glucometer's interface must be intuitive, displaying results and instructions easily. Some models have a touch screen, which is comfortable and convenient to use. The device should ideally be of a size and shape that allows for a good grip.

2. Easy transportation: Since patients need to measure their blood sugar levels anywhere and anytime during the day, the portability of the device is a very important consideration. Therefore, patients would prefer a lightweight and space-saving option. Weight should not be a constraining factor, especially for younger patients.

3. Blood glucose measurement units: Depending on the instrument model, results are given in g/l, mg/dl, or mmol/l. If diabetic patients are not careful about the selected measurement unit (in the case of multi-unit meters), they could be misled. Converting milligrams per deciliter to grams per liter is done by dividing the number by 100. For example, if the glucometer's unit is mg/dl and the displayed result is 123, it means the patient's capillary blood glucose level is 1.23 g/l. Converting mmol/l to g/l is done by multiplying mmol/l by 0.18.

4. Use of chips (or codes): For some glucometers, each box of test strips contains a specific chip that must be used and discarded after use. Incorrect adaptation of the meter/strip can lead to incorrect results. For meters requiring such adaptation, ensure that the displayed code matches the code on the test strip vial before each measurement. If not, measurement should not be conducted. Some models do not require code input to ensure the quality of results.

What is the measurement principle of a glucometer?

There are currently several measurement techniques on the market. Mainly electrochemical (enzymatic) methods, divided into three categories: by glucose oxidase, by glucose dehydrogenase, and by glucose dye oxidoreductase. The obtained results can differ depending on the used technique. Therefore, using test strips that are compatible with the technique displayed on the meter is always very important. 

Similarly, these different types of techniques may interfere with other treatments of some patients. For example, glucose oxidase meters interfere with oxygen therapy. Meters using glucose-dye-oxidoreductase are interfered with by maltose and galactose, as well as polysaccharides or oligosaccharides present in infusions. Maltose can be present in high concentrations in the blood directly (immunoglobulin preparations) or after metabolism (e.g., icodextrin used in peritoneal dialysis). Therefore, the risk of overestimating blood glucose results is very high and should not be taken lightly. Usually, these contraindications are marked on relevant glucometers, such as the prohibition of using such devices in the case of peritoneal dialysis.